dst_hmac_link.c

   1 #ifdef HMAC_MD5
   2 #ifndef __APPLE__
   3 #ifndef LINT
   4 static const char rcsid[] = "$Header: /Users/Shared/libresolv_2/libresolv/dst_hmac_link.c,v 1.1 2006/03/01 19:01:36 majka Exp $";
   5 #endif
   6 #endif
   7
   8 /*
   9  * Portions Copyright (c) 1995-1998 by Trusted Information Systems, Inc.
  10  *
  11  * Permission to use, copy modify, and distribute this software for any
  12  * purpose with or without fee is hereby granted, provided that the above
  13  * copyright notice and this permission notice appear in all copies.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS" AND TRUSTED INFORMATION SYSTEMS
  16  * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL
  18  * TRUSTED INFORMATION SYSTEMS BE LIABLE FOR ANY SPECIAL, DIRECT,
  19  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
  20  * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
  21  * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
  22  * WITH THE USE OR PERFORMANCE OF THE SOFTWARE.
  23  */
  24
  25 /*
  26  * This file contains an implementation of the HMAC-MD5 algorithm.
  27  */
  28 #ifndef __APPLE__
  29 #include "port_before.h"
  30 #endif
  31
  32 #include <stdio.h>
  33 #include <unistd.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36 #include <memory.h>
  37 #include <sys/param.h>
  38 #include <sys/time.h>
  39 #include <netinet/in.h>
  40 #include <arpa/nameser.h>
  41 #include <resolv.h>
  42
  43 #include "dst_internal.h"
  44 #ifdef USE_MD5
  45 # include "md5.h"
  46 # ifndef _MD5_H_
  47 #  define _MD5_H_ 1     /* make sure we do not include rsaref md5.h file */
  48 # endif
  49 #endif
  50
  51 #ifndef __APPLE__
  52 #include "port_after.h"
  53 #endif
  54
  55
  56 #define HMAC_LEN        64
  57 #define HMAC_IPAD       0x36
  58 #define HMAC_OPAD       0x5c
  59 #define MD5_LEN         16
  60
  61
  62 typedef struct hmackey {
  63         u_char hk_ipad[64], hk_opad[64];
  64 } HMAC_Key;
  65
  66
  67 /**************************************************************************
  68  * dst_hmac_md5_sign
  69  *     Call HMAC signing functions to sign a block of data.
  70  *     There are three steps to signing, INIT (initialize structures),
  71  *     UPDATE (hash (more) data), FINAL (generate a signature).  This
  72  *     routine performs one or more of these steps.
  73  * Parameters
  74  *     mode     SIG_MODE_INIT, SIG_MODE_UPDATE and/or SIG_MODE_FINAL.
  75  *     priv_key    key to use for signing.
  76  *     context   the context to be used in this digest
  77  *     data     data to be signed.
  78  *     len       length in bytes of data.
  79  *     signature   location to store signature.
  80  *     sig_len     size of the signature location
  81  * returns
  82  *      N  Success on SIG_MODE_FINAL = returns signature length in bytes
  83  *      0  Success on SIG_MODE_INIT  and UPDATE
  84  *       <0  Failure
  85  */
  86
  87 static int
  88 dst_hmac_md5_sign(const int mode, DST_KEY *d_key, void **context,
  89                   const u_char *data, const int len,
  90                   u_char *signature, const int sig_len)
  91 {
  92         HMAC_Key *key;
  93         int sign_len = 0;
  94         MD5_CTX *ctx = NULL;
  95
  96         if (mode & SIG_MODE_INIT)
  97                 ctx = (MD5_CTX *) malloc(sizeof(*ctx));
  98         else if (context)
  99                 ctx = (MD5_CTX *) *context;
 100         if (ctx == NULL)
 101                 return (-1);
 102
 103         if (d_key == NULL || d_key->dk_KEY_struct == NULL)
 104                 return (-1);
 105         key = (HMAC_Key *) d_key->dk_KEY_struct;
 106
 107         if (mode & SIG_MODE_INIT) {
 108                 MD5Init(ctx);
 109                 MD5Update(ctx, key->hk_ipad, HMAC_LEN);
 110         }
 111
 112         if ((mode & SIG_MODE_UPDATE) && (data && len > 0))
 113                 MD5Update(ctx, data, len);
 114
 115         if (mode & SIG_MODE_FINAL) {
 116                 if (signature == NULL || sig_len < MD5_LEN)
 117                         return (SIGN_FINAL_FAILURE);
 118                 MD5Final(signature, ctx);
 119
 120                 /* perform outer MD5 */
 121                 MD5Init(ctx);
 122                 MD5Update(ctx, key->hk_opad, HMAC_LEN);
 123                 MD5Update(ctx, signature, MD5_LEN);
 124                 MD5Final(signature, ctx);
 125                 sign_len = MD5_LEN;
 126                 SAFE_FREE(ctx);
 127         }
 128         else {
 129                 if (context == NULL)
 130                         return (-1);
 131                 *context = (void *) ctx;
 132         }
 133         return (sign_len);
 134 }
 135
 136
 137 /**************************************************************************
 138  * dst_hmac_md5_verify()
 139  *     Calls HMAC verification routines.  There are three steps to
 140  *     verification, INIT (initialize structures), UPDATE (hash (more) data),
 141  *     FINAL (generate a signature).  This routine performs one or more of
 142  *     these steps.
 143  * Parameters
 144  *     mode     SIG_MODE_INIT, SIG_MODE_UPDATE and/or SIG_MODE_FINAL.
 145  *     dkey     key to use for verify.
 146  *     data     data signed.
 147  *     len       length in bytes of data.
 148  *     signature   signature.
 149  *     sig_len     length in bytes of signature.
 150  * returns
 151  *     0  Success
 152  *    <0  Failure
 153  */
 154
 155 static int
 156 dst_hmac_md5_verify(const int mode, DST_KEY *d_key, void **context,
 157                 const u_char *data, const int len,
 158                 const u_char *signature, const int sig_len)
 159 {
 160         HMAC_Key *key;
 161         MD5_CTX *ctx = NULL;
 162
 163         if (mode & SIG_MODE_INIT)
 164                 ctx = (MD5_CTX *) malloc(sizeof(*ctx));
 165         else if (context)
 166                 ctx = (MD5_CTX *) *context;
 167         if (ctx == NULL)
 168                 return (-1);
 169
 170         if (d_key == NULL || d_key->dk_KEY_struct == NULL)
 171                 return (-1);
 172
 173         key = (HMAC_Key *) d_key->dk_KEY_struct;
 174         if (mode & SIG_MODE_INIT) {
 175                 MD5Init(ctx);
 176                 MD5Update(ctx, key->hk_ipad, HMAC_LEN);
 177         }
 178         if ((mode & SIG_MODE_UPDATE) && (data && len > 0))
 179                 MD5Update(ctx, data, len);
 180
 181         if (mode & SIG_MODE_FINAL) {
 182                 u_char digest[MD5_LEN];
 183                 if (signature == NULL || key == NULL || sig_len != MD5_LEN)
 184                         return (VERIFY_FINAL_FAILURE);
 185                 MD5Final(digest, ctx);
 186
 187                 /* perform outer MD5 */
 188                 MD5Init(ctx);
 189                 MD5Update(ctx, key->hk_opad, HMAC_LEN);
 190                 MD5Update(ctx, digest, MD5_LEN);
 191                 MD5Final(digest, ctx);
 192
 193                 SAFE_FREE(ctx);
 194                 if (memcmp(digest, signature, MD5_LEN) != 0)
 195                         return (VERIFY_FINAL_FAILURE);
 196         }
 197         else {
 198                 if (context == NULL)
 199                         return (-1);
 200                 *context = (void *) ctx;
 201         }
 202         return (0);
 203 }
 204
 205
 206 /**************************************************************************
 207  * dst_buffer_to_hmac_md5
 208  *     Converts key from raw data to an HMAC Key
 209  *     This function gets in a pointer to the data
 210  * Parameters
 211  *     hkey     the HMAC key to be filled in
 212  *     key      the key in raw format
 213  *     keylen   the length of the key
 214  * Return
 215  *      0       Success
 216  *      <0      Failure
 217  */
 218 static int
 219 dst_buffer_to_hmac_md5(DST_KEY *dkey, const u_char *key, const int keylen)
 220 {
 221         int i;
 222         HMAC_Key *hkey = NULL;
 223         MD5_CTX ctx;
 224         int local_keylen = keylen;
 225
 226         if (dkey == NULL || key == NULL || keylen < 0)
 227                 return (-1);
 228
 229         if ((hkey = (HMAC_Key *) malloc(sizeof(HMAC_Key))) == NULL)
 230                   return (-2);
 231
 232         memset(hkey->hk_ipad, 0, sizeof(hkey->hk_ipad));
 233         memset(hkey->hk_opad, 0, sizeof(hkey->hk_opad));
 234
 235         /* if key is longer than HMAC_LEN bytes reset it to key=MD5(key) */
 236         if (keylen > HMAC_LEN) {
 237                 u_char tk[MD5_LEN];
 238                 MD5Init(&ctx);
 239                 MD5Update(&ctx, key, keylen);
 240                 MD5Final(tk, &ctx);
 241                 memset((void *) &ctx, 0, sizeof(ctx));
 242                 key = tk;
 243                 local_keylen = MD5_LEN;
 244         }
 245         /* start out by storing key in pads */
 246         memcpy(hkey->hk_ipad, key, local_keylen);
 247         memcpy(hkey->hk_opad, key, local_keylen);
 248
 249         /* XOR key with hk_ipad and opad values */
 250         for (i = 0; i < HMAC_LEN; i++) {
 251                 hkey->hk_ipad[i] ^= HMAC_IPAD;
 252                 hkey->hk_opad[i] ^= HMAC_OPAD;
 253         }
 254         dkey->dk_key_size = local_keylen;
 255         dkey->dk_KEY_struct = (void *) hkey;
 256         return (1);
 257 }
 258
 259
 260 /**************************************************************************
 261  *  dst_hmac_md5_key_to_file_format
 262  *      Encodes an HMAC Key into the portable file format.
 263  *  Parameters
 264  *      hkey      HMAC KEY structure
 265  *      buff      output buffer
 266  *      buff_len  size of output buffer
 267  *  Return
 268  *      0  Failure - null input hkey
 269  *     -1  Failure - not enough space in output area
 270  *      N  Success - Length of data returned in buff
 271  */
 272
 273 static int
 274 dst_hmac_md5_key_to_file_format(const DST_KEY *dkey, char *buff,
 275                             const int buff_len)
 276 {
 277         char *bp;
 278         int len, b_len, i, key_len;
 279         u_char key[HMAC_LEN];
 280         HMAC_Key *hkey;
 281
 282         if (dkey == NULL || dkey->dk_KEY_struct == NULL)
 283                 return (0);
 284         if (buff == NULL || buff_len <= (int) strlen(key_file_fmt_str))
 285                 return (-1);    /* no OR not enough space in output area */
 286
 287         hkey = (HMAC_Key *) dkey->dk_KEY_struct;
 288         memset(buff, 0, buff_len);      /* just in case */
 289         /* write file header */
 290         sprintf(buff, key_file_fmt_str, KEY_FILE_FORMAT, KEY_HMAC_MD5, "HMAC");
 291
 292         bp = (char *) strchr(buff, '\0');
 293         b_len = buff_len - (bp - buff);
 294
 295         memset(key, 0, HMAC_LEN);
 296         for (i = 0; i < HMAC_LEN; i++)
 297                 key[i] = hkey->hk_ipad[i] ^ HMAC_IPAD;
 298         for (i = HMAC_LEN - 1; i >= 0; i--)
 299                 if (key[i] != 0)
 300                         break;
 301         key_len = i + 1;
 302
 303         strcat(bp, "Key: ");
 304         bp += strlen("Key: ");
 305         b_len = buff_len - (bp - buff);
 306
 307         len = b64_ntop(key, key_len, bp, b_len);
 308         if (len < 0)
 309                 return (-1);
 310         bp += len;
 311         *(bp++) = '\n';
 312         *bp = '\0';
 313         b_len = buff_len - (bp - buff);
 314
 315         return (buff_len - b_len);
 316 }
 317
 318
 319 /**************************************************************************
 320  * dst_hmac_md5_key_from_file_format
 321  *     Converts contents of a key file into an HMAC key.
 322  * Parameters
 323  *     hkey    structure to put key into
 324  *     buff       buffer containing the encoded key
 325  *     buff_len   the length of the buffer
 326  * Return
 327  *     n >= 0 Foot print of the key converted
 328  *     n <  0 Error in conversion
 329  */
 330
 331 static int
 332 dst_hmac_md5_key_from_file_format(DST_KEY *dkey, const char *buff,
 333                               const int buff_len)
 334 {
 335         const char *p = buff, *eol;
 336         u_char key[HMAC_LEN+1]; /* b64_pton needs more than 64 bytes do decode
 337                                                          * it should probably be fixed rather than doing
 338                                                          * this
 339                                                          */
 340         u_char *tmp;
 341         int key_len, len;
 342
 343         if (dkey == NULL)
 344                 return (-2);
 345         if (buff == NULL || buff_len < 0)
 346                 return (-1);
 347
 348         memset(key, 0, sizeof(key));
 349
 350         if (!dst_s_verify_str(&p, "Key: "))
 351                 return (-3);
 352
 353         eol = strchr(p, '\n');
 354         if (eol == NULL)
 355                 return (-4);
 356         len = eol - p;
 357         tmp = malloc(len + 2);
 358         memcpy(tmp, p, len);
 359         *(tmp + len) = 0x0;
 360         key_len = b64_pton((char *)tmp, key, HMAC_LEN+1);       /* see above */
 361         SAFE_FREE2(tmp, len + 2);
 362
 363         if (dst_buffer_to_hmac_md5(dkey, key, key_len) < 0) {
 364                 return (-6);
 365         }
 366         return (0);
 367 }
 368
 369 /*
 370  * dst_hmac_md5_to_dns_key()
 371  *         function to extract hmac key from DST_KEY structure
 372  * intput:
 373  *      in_key:  HMAC-MD5 key
 374  * output:
 375  *      out_str: buffer to write ot
 376  *      out_len: size of output buffer
 377  * returns:
 378  *      number of bytes written to output buffer
 379  */
 380 static int
 381 dst_hmac_md5_to_dns_key(const DST_KEY *in_key, u_char *out_str,
 382                         const int out_len)
 383 {
 384
 385         HMAC_Key *hkey;
 386         int i;
 387
 388         if (in_key == NULL || in_key->dk_KEY_struct == NULL ||
 389             out_len <= in_key->dk_key_size || out_str == NULL)
 390                 return (-1);
 391
 392         hkey = (HMAC_Key *) in_key->dk_KEY_struct;
 393         for (i = 0; i < in_key->dk_key_size; i++)
 394                 out_str[i] = hkey->hk_ipad[i] ^ HMAC_IPAD;
 395         return (i);
 396 }
 397
 398 /**************************************************************************
 399  *  dst_hmac_md5_compare_keys
 400  *      Compare two keys for equality.
 401  *  Return
 402  *      0         The keys are equal
 403  *      NON-ZERO   The keys are not equal
 404  */
 405
 406 static int
 407 dst_hmac_md5_compare_keys(const DST_KEY *key1, const DST_KEY *key2)
 408 {
 409         HMAC_Key *hkey1 = (HMAC_Key *) key1->dk_KEY_struct;
 410         HMAC_Key *hkey2 = (HMAC_Key *) key2->dk_KEY_struct;
 411         return memcmp(hkey1->hk_ipad, hkey2->hk_ipad, HMAC_LEN);
 412 }
 413
 414 /**************************************************************************
 415  * dst_hmac_md5_free_key_structure
 416  *     Frees all (none) dynamically allocated structures in hkey
 417  */
 418
 419 static void *
 420 dst_hmac_md5_free_key_structure(void *key)
 421 {
 422         HMAC_Key *hkey = key;
 423         SAFE_FREE(hkey);
 424         return (NULL);
 425 }
 426
 427
 428 /***************************************************************************
 429  * dst_hmac_md5_generate_key
 430  *     Creates a HMAC key of size size with a maximum size of 63 bytes
 431  *     generating a HMAC key larger than 63 bytes makes no sense as that key
 432  *     is digested before use.
 433  */
 434
 435 static int
 436 dst_hmac_md5_generate_key(DST_KEY *key, const int nothing)
 437 {
 438         (void)key;
 439         (void)nothing;
 440         return (-1);
 441 }
 442
 443 /*
 444  * dst_hmac_md5_init()  Function to answer set up function pointers for HMAC
 445  *         related functions
 446  */
 447 int
 448 dst_hmac_md5_init()
 449 {
 450         if (dst_t_func[KEY_HMAC_MD5] != NULL)
 451                 return (1);
 452         dst_t_func[KEY_HMAC_MD5] = malloc(sizeof(struct dst_func));
 453         if (dst_t_func[KEY_HMAC_MD5] == NULL)
 454                 return (0);
 455         memset(dst_t_func[KEY_HMAC_MD5], 0, sizeof(struct dst_func));
 456         dst_t_func[KEY_HMAC_MD5]->sign = dst_hmac_md5_sign;
 457         dst_t_func[KEY_HMAC_MD5]->verify = dst_hmac_md5_verify;
 458         dst_t_func[KEY_HMAC_MD5]->compare = dst_hmac_md5_compare_keys;
 459         dst_t_func[KEY_HMAC_MD5]->generate = dst_hmac_md5_generate_key;
 460         dst_t_func[KEY_HMAC_MD5]->destroy = dst_hmac_md5_free_key_structure;
 461         dst_t_func[KEY_HMAC_MD5]->to_dns_key = dst_hmac_md5_to_dns_key;
 462         dst_t_func[KEY_HMAC_MD5]->from_dns_key = dst_buffer_to_hmac_md5;
 463         dst_t_func[KEY_HMAC_MD5]->to_file_fmt = dst_hmac_md5_key_to_file_format;
 464         dst_t_func[KEY_HMAC_MD5]->from_file_fmt = dst_hmac_md5_key_from_file_format;
 465         return (1);
 466 }
 467
 468 #else
 469 #include "dst_internal.h"
 470 #define dst_hmac_md5_init res_9_dst_hmac_md5_init
 471 int
 472 dst_hmac_md5_init(){
 473         return (0);
 474 }
 475 #endif